Add FOV_3D_Z_RANGE option to limit the vertical range of 3D vision (#…

…31802)

* * add FOV_3D_Z_RANGE option. Minimum 0, maximum OVERMAP_LAYERS,
default 4.
* add logic to cast_zlight_segment that allows us to stop casting light
segments beyond FOV_3D_Z_RANGE levels. Decent speedup!

src/game.cpp

@@ -6639,6 +6639,8 @@ look_around_result game::look_around( catacurses::window w_info, tripoint &cente
     ctxt.register_action( "zoom_in" );
 
     const int old_levz = get_levz();
+    const int min_levz = std::max( old_levz - fov_3d_z_range, -OVERMAP_DEPTH );
+    const int max_levz = std::min( old_levz + fov_3d_z_range, OVERMAP_HEIGHT );
 
     m.update_visibility_cache( old_levz );
     const visibility_variables &cache = g->m.get_visibility_variables_cache();
@@ -6729,8 +6731,8 @@ look_around_result game::look_around( catacurses::window w_info, tripoint &cente
             }
 
             const int dz = ( action == "LEVEL_UP" ? 1 : -1 );
-            lz = clamp( lz + dz, -OVERMAP_DEPTH, OVERMAP_HEIGHT );
-            center.z = clamp( center.z + dz, -OVERMAP_DEPTH, OVERMAP_HEIGHT );
+            lz = clamp( lz + dz, min_levz, max_levz );
+            center.z = clamp( center.z + dz, min_levz, max_levz );
 
             add_msg( m_debug, "levx: %d, levy: %d, levz :%d", get_levx(), get_levy(), center.z );
             u.view_offset.z = center.z - u.posz();

src/game.h

@@ -44,6 +44,7 @@ extern std::unique_ptr<game> g;
 extern bool trigdist;
 extern bool use_tiles;
 extern bool fov_3d;
+extern int fov_3d_z_range;
 extern bool tile_iso;
 
 extern const int core_version;

src/lightmap.cpp

@@ -708,7 +708,7 @@ void cast_zlight_segment(
         T current_transparency = 0.0f;
 
         // TODO: Precalculate min/max delta.z based on start/end and distance
-        for( delta.z = 0; delta.z <= distance; delta.z++ ) {
+        for( delta.z = 0; delta.z <= std::min( fov_3d_z_range, distance ); delta.z++ ) {
             float trailing_edge_major = ( delta.z - 0.5f ) / ( delta.y + 0.5f );
             float leading_edge_major = ( delta.z + 0.5f ) / ( delta.y - 0.5f );
             current.z = offset.z + delta.x * 00 + delta.y * 00 + delta.z * zz;

src/options.cpp

@@ -47,6 +47,7 @@ bool log_from_top;
 int message_ttl;
 int message_cooldown;
 bool fov_3d;
+int fov_3d_z_range;
 bool tile_iso;
 
 std::map<std::string, std::string> TILESETS; // All found tilesets: <name, tileset_dir>
@@ -1872,6 +1873,14 @@ void options_manager::add_options_debug()
          false
        );
 
+    add( "FOV_3D_Z_RANGE", "debug", translate_marker( "Vertical range of 3D field of vision" ),
+         translate_marker( "How many levels up and down the experimental 3D field of vision reaches.  (This many levels up, this many levels down.)  3D vision of the full height of the world can slow the game down a lot.  Seeing fewer Z-levels is faster." ),
+         0, OVERMAP_LAYERS, 4
+       );
+
+    get_option( "FOV_3D_Z_RANGE" ).setPrerequisite( "FOV_3D" );
+
+
     add( "ENCODING_CONV", "debug", translate_marker( "Experimental path name encoding conversion" ),
          translate_marker( "If true, file path names are going to be transcoded from system encoding to UTF-8 when reading and will be transcoded back when writing.  Mainly for CJK Windows users." ),
          true
@@ -2809,6 +2818,7 @@ bool options_manager::save()
     message_ttl = ::get_option<int>( "MESSAGE_TTL" );
     message_cooldown = ::get_option<int>( "MESSAGE_COOLDOWN" );
     fov_3d = ::get_option<bool>( "FOV_3D" );
+    fov_3d_z_range = ::get_option<int>( "FOV_3D_Z_RANGE" );
 
     update_music_volume();
 
@@ -2841,6 +2851,7 @@ void options_manager::load()
     message_ttl = ::get_option<int>( "MESSAGE_TTL" );
     message_cooldown = ::get_option<int>( "MESSAGE_COOLDOWN" );
     fov_3d = ::get_option<bool>( "FOV_3D" );
+    fov_3d_z_range = ::get_option<int>( "FOV_3D_Z_RANGE" );
 #if defined(SDL_SOUND)
     sounds::sound_enabled = ::get_option<bool>( "SOUND_ENABLED" );
 #endif